在 Razor Page .Net Core 2.1 中删除 asp-page 中缺少 asp-route-id 值

Question

We have this very weird TournamentBatch Razor Page (index.cshtml) where we have something like this:

<td>
                <a asp-page="/TournamentBatchItems/Index" asp-route-id="@item.TournamentBatchID">Items</a> |
                <a asp-page="./Edit" asp-route-id="@item.TournamentBatchID">Edit</a> |
                <a asp-page="./Details" asp-route-id="@item.TournamentBatchID">Details</a> |
                <a asp-page="./Delete" asp-route-id="@item.TournamentBatchID">Delete</a>
            </td>

and when we are running this and end up that there is no id returned on the page just for /Delete link and other links are ok (/TournamentBatchItems/Index, /Edit, /Details).

This is the html source looks like:

<td>
                <a href="/TournamentBatchItems?id=5088415a-f491-4438-1aa9-08d642f7dffe">Items</a> |
                <a href="/TournamentBatches/Edit?id=5088415a-f491-4438-1aa9-08d642f7dffe">Edit</a> |
                <a href="/TournamentBatches/Details?id=5088415a-f491-4438-1aa9-08d642f7dffe">Details</a> |
                <a href="">Delete</a> |
            </td>

Now other pages for Delete are OK only this page. ?!?!

Any ideas?

Index Pagemodel:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.EntityFrameworkCore;
using AthlosifyWebArchery.Data;
using AthlosifyWebArchery.Models;
using AthlosifyWebArchery.Utilities;
using CsvHelper;
using System.IO;

namespace AthlosifyWebArchery.Pages.TournamentBatches
{
    public class IndexModel : PageModel
    {
        private readonly AthlosifyWebArchery.Data.ApplicationDbContext _context;

        public IndexModel(AthlosifyWebArchery.Data.ApplicationDbContext context)
        {
            _context = context;
        }

        public IList<TournamentBatch> TournamentBatches { get;set; }

        public async Task OnGetAsync()
        {
            TournamentBatches = await _context.TournamentBatch.ToListAsync();
        }



    }
}

Delete Pagemodel:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.EntityFrameworkCore;
using AthlosifyWebArchery.Data;
using AthlosifyWebArchery.Models;

namespace AthlosifyWebArchery.Pages.TournamentBatches
{
    public class DeleteModel : PageModel
    {
        private readonly AthlosifyWebArchery.Data.ApplicationDbContext _context;

        public DeleteModel(AthlosifyWebArchery.Data.ApplicationDbContext context)
        {
            _context = context;
        }

        [BindProperty]
        public TournamentBatch TournamentBatch { get; set; }
        public string ConcurrencyErrorMessage { get; set; }

        public async Task<IActionResult> OnGetAsync(Guid? id, bool? concurrencyError)
        {
            if (id == null)
            {
                return NotFound();
            }

            TournamentBatch = await _context.TournamentBatch
                                        .AsNoTracking() //Addded
                                        .FirstOrDefaultAsync(m => m.TournamentBatchID == id);

            if (TournamentBatch == null)
            {
                return NotFound();
            }

            if (concurrencyError.GetValueOrDefault())
            {
                ConcurrencyErrorMessage = "The record you attempted to delete "
                  + "was modified by another user after you selected delete. "
                  + "The delete operation was canceled and the current values in the "
                  + "database have been displayed. If you still want to delete this "
                  + "record, click the Delete button again.";
            }

            return Page();
        }

        public async Task<IActionResult> OnPostAsync(Guid? id)
        {
            /*if (id == null)
            {
                return NotFound();
            }

            TournamentBatch = await _context.TournamentBatch.FindAsync(id);

            if (TournamentBatch != null)
            {
                _context.TournamentBatch.Remove(TournamentBatch);
                await _context.SaveChangesAsync();
            }

            return RedirectToPage("./Index");
            */

            try
            {
                if (await _context.TournamentBatch.AnyAsync(
                    m => m.TournamentBatchID == id))
                {
                    // Department.rowVersion value is from when the entity
                    // was fetched. If it doesn't match the DB, a
                    // DbUpdateConcurrencyException exception is thrown.
                    _context.TournamentBatch.Remove(TournamentBatch);
                    await _context.SaveChangesAsync();
                }
                return RedirectToPage("./Index");
            }
            catch (DbUpdateConcurrencyException)
            {
                return RedirectToPage("./Delete",
                    new { concurrencyError = true, id = id });
            }
        }
    }
}

Answer 1

Reference: Anchor Tag Helper

Usually this happens when the anchor tag helper (in this case, asp-page) can't find the page or can't resolve the route through the default route conventions (you can find more details, or how to customize the conventions here

First check and make sure your Delete.cshtml page is in the same spot as Edit.cshtml and Details.cshtml (since they are working, and you used the same relative path for all 3.)

Also check and that you've started your page with the @page directive, and that your page directive is in the correct syntax which matches the appropriate method signature in your PageModel

example: @page "{id:int}"

public IActionResult OnGet(int id) 
{
...
}